Mercedes-Benz
SL 73 AMG (R129)

Why it matters

The SL 73 AMG was an AMG conversion of the R 129 SL 600 that replaced its 6.0-litre V12 with a 7.3-litre unit rated at 525 hp. It was never officially marketed, and the cached auction lots say its engine was also supplied to Pagani for the Zonda. Production figures differ between sources and the factory archive does not state one.

How rare is it?

Six separate kinds of rarity – never combined into one number.

Each kind of rarity is rated separately and never combined.

Photos

Exterior, interior and detail photos with their licences.

• Mercedes-Benz SL 73 AMG (R129) (Wikimedia Commons search)
  Photo: nakhon100 · CC BY 2.0
• Mercedes-Benz SL 73 AMG (R129) (Wikimedia Commons search)
  Photo: nakhon100 · CC BY 2.0
• Mercedes-Benz SL 73 AMG (R129) (Wikimedia Commons search)
  Photo: M 93 · Public domain

Production

Every figure says what it counts.

Independent counts (e.g. engine and colour) are never combined into a calculated figure. Surviving examples are never presented as original production.

History

The archive lists the SL 73 AMG as design name R 129 E 73, type 129.076, produced from April 1999 to May 2001, and prices the conversion at DM 99,180 (April 1999) on top of an SL 600. The engine is the M 120 E 73, 7291 cc with 91.5 x 92.4 mm bore and stroke, driving the rear wheels through a five-speed automatic.

RM Sotheby's describes the car as a bored-out SL 600 engine with uprated internals and revised brakes and damping. One 1999 car was delivered new to a Japanese collector in October 1999. The production count is disputed: the RM lots say 42, 85, or 40 to 50 cars of a roughly 1,000-car run of AMG-modified R 129s, and the factory archive says it is not separately documented.

Technical specifications

Engine

Transmission & drivetrain

Chassis, body & dimensions

Performance

“Not yet verified” means no source has been checked for that value yet. Nothing is estimated to fill a gap.

Identification guide

How to tell an original from a replica or later conversion.

The factory data lists engine type M 120 E 73 / 120.990 and 8.5 J x 18 and 9.5 J x 18 wheels with 245/40 ZR 18 and 275/35 ZR 18 tyres. RM Sotheby's describes the visible clues as twin chrome exhaust tips, a discreet body kit, small exterior badging and AMG wheels, plus a 300 km/h speedometer with a central AMG logo. Engine numbers quoted in two RM lots take the form "AMG 0087 7,3" and "AMG 0106 7,3", and one car came with a Mercedes-AMG Homologation Certificate.

Sources

Each number links to the exact facts it supports.

1. 1
   MercedesBlog – Top 10 most limited edition Mercedes-Benz models (6) Level C

   • 85 units

   Accessed 2026-11-11
2. 2
   SL 73 AMG / R 129 E 73, 1999 - 2001 (Classic M@RS) Level A Mercedes-Benz Group AG (Classic M@RS, Mercedes-Benz Public Archive)

   • Engine type : M 120 E 73 / 120.990 (Technical data)
   • Number of cylinders / arrangement : 12 / 60° V; light-alloy block (Technical data)
   • Total displacement : 7291 cc (Technical data)
   • Bore x Stroke : 91.5 x 92.4 mm (Technical data)
   • Compression ratio : 10.5 (Technical data)
   • Number of valves / arrangement : 2 intake, 2 exhaust / V-shaped overhead (Technical data)
   • Valve operation : 2 overhead camshafts per cylinder bank (intake camshafts adjustable) (Technical data)
   • Fuel system : microprocessor controlled injection system with hot-film air mass sensor (Bosch ME engine (Technical data)
   • Rated output : 386 kW / 525 hp at 5500 rpm (Technical data)
   • Rated torque : 750 Nm at 4000 rpm (Technical data)
   • Gearing : 5-speed automatic transmission (Technical data)
   • Gear ratios : I. 3.59; II. 2.19; III. 1.41; IV. 1.0; V. 0.83; R. 3.16 (Technical data)
   • Final drive ratio : 2.65 (Technical data)
   • Driven wheels : rear wheels (Technical data)
   • Frame design : steel unit body (Technical data)
   • Front-wheel suspension : A-arm / spring strut with hydropneumatic level control (Technical data)
   • Rear-wheel suspension : multilink suspension with hydropneumatic level control (Technical data)
   • Brake system (foot brake) : hydraulic dual-circuit brake system with vacuum booster, antilock system and (Technical data)
   • Steering : recirculating-ball power steering (Technical data)
   • Wheelbase : 2515 mm (Technical data)
   • Length : 4499 mm (Technical data)
   • Width : 1812 mm (Technical data)
   • Height : 1296 mm (with cabriolet top closed) (Technical data)
   • Front / rear track : 1553 / 1541 mm (Technical data)
   • Kerb weight : 2050 kg (Technical data)
   • Maximum speed : 250 km/h (electronically governed) (Technical data)
   • Acceleration 0-100 km/h : 4.8 s (Technical data)
   • Fuel consumption : 24.5 / 11.4 / 15.9 l (Technical data)

   Accessed 2026-11-12